1. Field of the Invention
The present invention relates to telecommunications and, more particularly, to methods of communicating with mobile stations such as cellular telephones, personal digital assistants (PDAs), cellular modems, and personal computers for instance.
2. Description of Related Art
Traditionally, each mobile station in a telecommunications network is associated with a unique Electronic Serial Number (ESN) and a unique Mobile Identification Number (MIN). The ESN, which is typically hard-coded into the mobile station, identifies the mobile station as a unique physical device and usually includes a manufacturer code and a manufacturer-assigned serial number. The MIN, on the other hand, is typically assigned to the mobile station by a service provider and functions as a subscriber ID for billing and for receiving calls. In many cases, the MIN will be a telephone directory number.
When a call is placed to a mobile station, a service carrier may alert the mobile station by broadcasting a paging message that is keyed to the MIN of the mobile station. The mobile station may then detect its MIN in the paging message and respond to the incoming call. On the other hand, when a call is placed from the mobile station, the mobile station typically transmits both its ESN and its MIN to the service provider. The service provider may then authenticate the ESN/MIN pair and responsively allow the call to proceed.
With the growing popularity of mobile communications, individual users of mobile stations are finding themselves with multiple different mobile stations, each having been assigned a respective MIN. For instance, a user may have a cellular telephone with one MIN, a PCMCIA-card wireless modem with another MIN, and a PDA wireless modem adapter with yet another MIN. Notwithstanding the fact that each of these separate devices will have a unique ESN, each device under existing arrangements would also have a unique MIN.
The resulting proliferation of MINs is likely to present a problem for telecommunication service providers. Already, the quantity of available directory numbers throughout many areas is beginning to dwindle. The allocation of many more MINs for mobile communication devices will only further diminish the pool of available directory numbers.